I personally had to go through this a couple years myself. It was night, my wife was on a business trip, and I was suddenly stricken with agonizing abdominal pain. I couldn't even move enough to reach the phone for hours, let alone unlock the front door. However, I did have plenty of time to envision fire fighters breaking down my door and worrying about what might happen to my house while I'm off at the ER with a busted front door. In my case, the pain eventually subsided enough for me to reach the phone and also unlock the front door.

I had thought of two other possibilities besides the lock box: a combination code lockset and keeping your garage door opener handy. The combination locksets can be programmed with any combination so memorize one to give to the dispatcher. With the garage door opener, even if you keep the door from the garage into the house locked, at least if EMS has to force the inner door, the garage door is still intact and can be closed again when everyone leaves.

Still, that's a tough situation and if it's truly an emergency, they have to do what they have to do to help you.